Accessibility to adequate, appropriate, and complete health-related information is one of the key components which allows program managers to take evidence-based decisions, plan for effective resource allocation, monitor and evaluate newer health strategies, and work towards holistic development of the society. [1],[2] It has been acknowledged that the most crucial indicator for a health-related information system is that it should be population based (viz. reflects the socio-demographic/economic/health attributes of the society). [3] Nevertheless, it remains extremely difficult to obtain the information at the population level. [2]

Globally, based on the quality of the public health infrastructure, prevalent morbidity-mortality pattern, and purpose, different sources of health information like sample registration system, notification, etc. have been employed. [1],[3] However, most of these sources of information lack important aspects of health and disease in the community, and thus population surveys are needed to supplement other sources of health information. [2] Population-based surveys usually aim to evaluate the health status of a population, explore the natural history of disease; and assess the different attributes of health care delivery services. [2],[4]

Currently, based on the evidence obtained from different population-based surveys (viz. screening for cancer, treatment-seeking behavior, prevalence of coronary artery disease or infectious diseases, etc.), different new initiatives or modifications in the existing strategies, such as identification of high-risk groups for a specific disease, finding the age at which screening for cancer should be initiated, making alterations in the frequency of screening tests, adoption of new line of management for a disease, initiation of innovative strategies to control the incidence of infectious disease, etc., have been implemented in heterogeneous settings. [5],[6],[7],[8]

Population surveys can either be cross-sectional or longitudinal, descriptive or analytic or both, and generally obtain data from a sampling unit like a household or a cohort. [9],[10] However, to ensure that results are applicable to the study population, the primary target is to select the study sample representative of the population. [10] The population surveys can be conducted by different methods as follows:

Face-to-face interview: Indicated for measuring subjective phenomena like perceived morbidity, disability, and impairment. Its advantage is that it does not require clinical person, but is time consuming and cannot be carried out on an extensive scale.

Clinical and biochemical examination: It can be employed when morbidity-related attributes have to be obtained. The elicited information is reliable; nevertheless, it is expensive, needs trained staff, and is difficult to apply on a large scale.

Health records survey: It is indicated to study the trends of a specific health condition. It is advantageous as it can be done quickly and does not require much financial support/a technical person. However, as there is no line listing or patient registry mechanism for most of the diseases, this cannot be applied to all health conditions. Furthermore, often the obtained information is incomplete (viz. wrong address) and unreliable owing to the absence of standardized mechanism to obtain data.

Self-administered/mailed questionnaire survey: This method has been employed because of its simplicity to apply, inexpensive nature, and no requirement for a trained person. Nevertheless, this method has a high rate of non-response. [2],[9],[11]

The epidemiologists have recommended use of these methods in combination to augment the completeness and reliability of data. [3] For instance, in order to obtain a comprehensive picture regarding nutritional assessment of a group of individuals, different methods like face-to-face interview (24-h dietary recall or food frequency questionnaire), clinical assessment, biochemical assessment (laboratory tests), and health records assessment (viz. inventory or food balance sheet) are used in combination. [3],[12] Finally, the collected data are converted into needed information by comparing them over time and place. [2],[3]

To conclude, population-based surveys are crucial to elicit health information from the level of community and, thus, deserve a key place in strengthening the public health system.